Robotic Spacecraft: Loaded for Bear or Barely Loaded?
by Dale M. Gray
When George Mallory was asked in 1923 why he was going climb Mount Everest, his immortal reply "Because it is there!" became the standard by which exploration before and since was measured. Mallory and his companion Andrew Irvine did indeed climb Mount Everest in 1924, but whether they reached the summit is not yet known. It is known that disaster befell the experienced mountain climber; on the way down from the attempt he met his death after a fall on the mountain.
So why evoke the ghost of Mallory in an editorial on space exploration? To point out that the cost of exploration is not measured merely in equipment, budgets, or man-hours. If a man, a company or a nation sets out to explore, disaster is one coin that must be paid and paid often. Columbus knew this fact and knew it well. School children know that he took three ships with him in 1492. Without the triple redundancy, he would not have made it back home.
History is filled with tales of men and women pushing into the unknown and never returning. Often they disappear with few lessons to be learned by those who followed, but sometimes the cause of their demise is learned by later explorers. When Mountain Men exploring the American West viewed the bleached bones of a fellow fur-trapper lying by the side of a desert water hole, they were little tempted to taste the water. When a new wing arrangement disintegrated in flight, few airplane designers would trust their lives to a similar wing.
At the point where civilization meets wilderness, known by the term "frontier", even the smallest of mistakes can snowball into catastrophe. Unlike civilization where mistakes tend to dampen out, on a frontier there is little if any infrastructure to provide support when things go awry. Frontiersmen, as a result, tended to be extremely self-reliant and carried all they needed or thought they might need. The phrase, "loaded for bear", was not a casual hunting term, rather a Mountain Man's way of saying he was prepared for the worst the frontier could offer, an encounter with the extremely dangerous grizzly bear.
While on a frontier, a person instantly reacting to problems can stay alive. On a frontier, dangers are known and preparations can be made ahead of time. The same is not true in wilderness. By definition, wilderness is traveling into the unknown. It would impossible to be "loaded for bear" if you had only experience with black bears and had never heard or even imagined a grizzly. In wilderness mistakes are often instantly fatal. Surviving the initial mistake is often not much better. With no resources or infrastructure, a damaged explorer is "as good as dead". When Mallory fell on the way down Everest, he survived the fall but suffered a broken leg. With no way to be rescued or to even warm himself, he succumbed to exposure.
Historically, planners of expeditions dealt with the fatal nature of wilderness by providing extra manpower and redundancy in their efforts. In the Mountain Men era of the American West, individual fur-trappers often died during their explorations, but exploration companies of which they were part were able to continue. When President Thomas Jefferson planned an expedition across the continent, he installed the redundant leadership of Lewis and Clark over a company of men so that if one leader or man was lost, the expedition could continue. In the early years of spaceflight, nearly identical spaceprobes were launched by both the US and USSR. . A partial list of explorers launched in the same window includes: Mariners 6 and 7, Mariners and 9, Vikings 1 and 2, Mars 2 and 3, Mars 4 and 5, Mars 6 and 7, Pioneers 10 and 11, and Voyagers 1 and 2. The redundancy of spacecraft worked to counter the unforeseeable catastrophic event that could and did occur. Mariner 8 was lost during launch. Mars 2 reached Mars, but transmitted no data, Mars 6 was lost and Mars 7 transmitted only 150 seconds during the descent to the Martian surface.
In the late 20th Century, the expected loss of human life in exploration has become unacceptable in Western Society. Andrew Chaikin's book "A Man on the Moon" speaks of the concern at NASA and higher levels of government over additional missions after the first successful Moon landing. Managers began to view each new mission as one more chance for disaster and damage to national prestige. By Apollo 17, many of the mission planners were relieved that they wouldn't have to throw the dice again. They had won the Cold War race to the Moon and there was little incentive to keep exploring.
The United States left the Moon and has only recently returned in the form of scientific, technological and even one commercial spacecraft. While many expected mankind to return to the Moon relatively quickly, retreat from wilderness is not unusual. After Mallory's death in 1924, 29 years passed before Edmund Hillary finally climbed Everest and returned safely.
Despite the long odds, human exploration has persisted through the ages. Curiosity, population pressure, greed, and desire for adventure have pushed men and women away from hearth and home and drawn them into the great unknown. They have succeeded or died individually, but society and humanity have benefited.
All through history, physical exploration of the unknown was equated with putting one's life on the line. But something new was added to the exploration equation in the late 20th Century. We no longer place ourselves on the line; we have gained the ability to explore remotely. We send our mechanized servants into the wilderness. We point them outward from the frontier and ask them to explore while we watch from the safety of civilization. While men and women continue to seek human presence at the forefront of knowledge, many of the hazards along the way have been paved over by the broken remains of our machines of exploration.
Advances in technology and exploration go hand in hand. Columbus had the benefit of new sailing and navigation technology. Mountain men had newly developed 50 caliber percussion cap rifles. Mallory and Irvine were the first to use oxygen to achieve Everest's highest slopes. In the late 20th Century, exploration technology has taken an additional import with machines standing in for human explorers. Technological frontiers had to be pushed outward to make Apollo possible. Even now, every robotic explorer of the depths of the ocean or of our solar system utilizes technology only slightly removed from the laboratory. Explorers such as Clementine and Deep Space 1 served as testing platforms for technology with exploration of the solar system as secondary goals.
The International community has sent a staggering variety of scientific probes of discovery this past decade. Most have had to endure minor malfunctions that threaten their missions, if not their existence. The Russian Mars 96 probe failed to achieve orbit when its fourth stage malfunctioned (FS 11/25/96). Clementine, a DOD technology demonstrator, successfully explored the Moon, but was lost on the way to an asteroid encounter when an archaic version of software was accidentally uplinked which caused the spacecraft to deplete its propellant. Mars Explorer disappeared from Radar when its propellant lines were pressurized; the craft is thought to have exploded. The recent loss of Mars Climate Orbiter illustrates the dangers of exploration. A minor mistake of English versus metric units caused the spacecraft to dip too deeply into the Martian atmosphere. The explorer was never heard from again.
Other spacecraft have been damaged, yet have been able part or all of their missions. Galileo is currently exploring the moons of Jupiter, but the mission was marred when the main antenna would not deploy. A low-gain antenna pressed into service and data compression software has allowed much of the mission's science to be salvaged. Mars Global Surveyor had a small problem with the extension of one of its solar panel that threatened its ability to aerobrake in the Martian atmosphere. Controllers were able to salvage the mission by slowing the rate of aerobraking, but at a cost of delaying the mapping of Mars by a year. The Japanese Nozomi spacecraft used more propellant than expected and as a result will arrive at Mars four years later than planned (FS 1/15/99). The Near Earth Asteroid Rendezvous (NEAR) spacecraft lost contact with Earth as it was about to make a critical final engine burn to put it in orbit around Eros (FS 12/25/98). The mission was salvaged, by rescheduling an encounter in February of 2000.
All of these missions were damaged, delayed or lost from very small, easy to correct mistakes. For example, it is unlikely in the extreme that NASA will ever allow English to metric conversion problem to affect a mission again. While several of the missions were destroyed before controllers even knew there was a problem, others were salvaged through over-engineering, double and triple redundant systems, hard work by dedicated professionals and a good dose of pure luck. They entered the wilderness as prepared as possible. However, these endeavors occurred in an arena where there are a nearly infinite number of possible trivial, but fatal, mistakes. Endless computer simulations can eliminate 99.999 percent of the predictable mistakes, but as history has proven, unforeseeable quirky mistakes cannot be simulated. Too high of a voltage applied during one test of an Apollo cryogenic tank nearly doomed Apollo 13. A Delta rocket exploded January 17, 1997 because one of its solid rocket booster's composite casings was dropped onto the floor of the factory from only a few feet. A military payload launched on a Titan IVB was lost on April 9, 1999 when a piece of tape was left on an electrical disconnect between upper stages. Careers will end and investigations will find causes, but there is simply no way to totally eliminate the threat of the infinite number of quirky, but fatal, scenarios that plague physical exploration.
Explorers can and do enter the wilderness and accomplish their missions unscathed. Lewis and Clark crossed the North American continent and lost only one man to appendicitis. But the mission was gone so long that President Jefferson wrote the entire expedition off as a failure. Lindbergh did cross the Atlantic solo in an airplane, but others who attempted the feat before him disappeared without a trace into the Atlantic. Today we remember solo space explorers such as Lunar Prospector and Mars Pathfinder that entered the wilderness and accomplished their missions and more. Their success was the result of hard work, endless simulations, quality redundant equipment and a good dose of luck. They also benefited from studying the telemetry from failed explorers who went before them. For other missions that are enroute, such as Deep Space 1, Cassini, and Mars Polar Lander, the jury is still out Apollo Society - Space Updates.
So what can be learned from the recent loss of Mars Climate Orbiter? The superficial solution of not mixing measuring units is of limited use. Rather a larger lesson is available for mission planners. Wilderness exploration should not be entered into lightly or ill equipped. By "by loading for bear" and maintaining aggressive vigilance at key moments, unexpected ill fortune may be averted or minimized. The use of robust and redundant critical systems seems to be a successful strategy. However, the main lesson learned from the history of exploration is that often individual explorers do not survive their encounter with the wilderness no matter what is done or how well prepared they embarked. Until the price of launch services drops to the point where swarms of explorers can be sent out, those who plan future missions must, like Thomas Jefferson before them, be willing to write off the whole mission on one turn of fate.